1. Field of the Invention
The present invention relates to a microscopic image apparatus, and in particular to a microscopic image apparatus or converting infrared light into visible light.
2. Description of the Related Art
FIG. 1 is a schematic view showing a conventional infrared microscopic image apparatus. The conventional infrared microscopic image apparatus uses the method of step-scan Fourier Transform infrared (FTIR) and includes an infrared object lens 1, an IR Michelson-type scan interferometer module 8, an infrared focal-plane array detector (IR FPA detector) 3, an infrared imaging lens 7 and an infrared source 2. The IR Michelson-type scan interferometer module 8 includes a beam splitter 8a, a stationary mirror 8b and a scan mirror 8c. When the infrared source 2 outputs infrared light to a sample 6 via the IR Michelson-type scan interferometer module 8, the infrared light 5, which is absorbed by sample 6, is detected and received by the infrared object lens 1 and the IR FPA detector 3. Then, the every pixel in the IR FPA detector 3 obtains multi-wavelength interference spectrum. The multi-wavelength interference spectrum is converted into infrared absorption spectrum of the sample by the method of Fourier transform. Nevertheless, the IR Michelson-type scan interferometer module 8 and the IR FPA detector 3 are very expensive. Thus, the infrared microscope is not widely used.
Consequently, the invention provides a low-cost microscopic image apparatus replacing the IR Michelson-type scan interferometer module 8 and the IR FPA detector 3 and obtaining the same infrared microscopic image.
An object of the invention is to provide a microscopic image apparatus for converting infrared light into visible light. The microscopic image apparatus comprises a sample stage, an infrared source, a dichroic mirror, an object lens for converting infrared light into visible light, a visible light source, a visible light imaging lens and a visible light image capturing device. The sample stage accommodates a sample. The infrared source outputs first infrared light to the sample. The first infrared light passes through the sample to create second infrared light having infrared absorption spectrum information of the sample. The object lens has an optical crystal and an infrared object lens. The infrared object lens receives the second infrared light having infrared absorption spectrum information of the sample and converts the second infrared light into parallel infrared light to enter the optical crystal. The visible light source outputs narrow band visible light to the optical crystal. In the optical crystal, the narrow band visible light and the second infrared light having infrared absorption spectrum information of the sample are coupled into sum-frequency light having a visible sum-frequency image. The visible light imaging lens projects the visible sum-frequency image on a predetermined position. The visible light image capturing device is disposed on the position to receive the visible sum-frequency image.
Preferably, the infrared object lens is an infrared infinity-corrected reflective object lens.
Preferably, the optical crystal is a nonlinear optical crystal.
Preferably, the optical crystal is a quasi-phase matching crystal.
Preferably, a dichroic film is formed on one side of the optical crystal. The narrow band visible light is reflected by the dichroic film and the parallel infrared light passes through the dichroic film,
Preferably, the microscopic image apparatus further comprises a dichroic mirror. The narrow band visible light is reflected to the object lens by the dichroic mirror and the sum-frequency light passes through the dichroic mirror.
Preferably, the microscopic image apparatus further comprises a optical filter protecting the narrow band visible light from receiving by the visible light image capturing device.
Preferably, the visible light source is a laser source, a light emitting diode or a laser diode.
Preferably, the visible light image capturing device is a CCD device.